Bump rack from 2.2.9 to 3.1.7

Bumps [rack](https://github.com/rack/rack) from 2.2.9 to 3.1.7.
- [Release notes](https://github.com/rack/rack/releases)
- [Changelog](https://github.com/rack/rack/blob/main/CHANGELOG.md)
- [Commits](rack/rack@v2.2.9...v3.1.7)

---
updated-dependencies:
- dependency-name: rack
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile

@@ -161,7 +161,7 @@ end
 group :production do
   gem 'unicorn'
   # Unicorn is incompatible with Rack 3, but doesn't specify it explicitly…
-  gem 'rack', '~> 2'
+  gem 'rack', '~> 3'
   gem 'newrelic_rpm'
   gem 'wkhtmltopdf-binary-ng'
 end

Gemfile.lock

@@ -542,18 +542,18 @@ GEM
       nio4r (~> 2.0)
     raabro (1.4.0)
     racc (1.8.1)
-    rack (2.2.9)
+    rack (3.1.7)
     rack-cors (2.0.2)
       rack (>= 2.0.0)
     rack-proxy (0.7.7)
       rack
-    rack-session (1.0.2)
-      rack (< 3)
+    rack-session (2.0.0)
+      rack (>= 3.0.0)
     rack-test (2.1.0)
       rack (>= 1.3)
-    rackup (1.0.0)
-      rack (< 3)
-      webrick
+    rackup (2.1.0)
+      rack (>= 3)
+      webrick (~> 1.8)
     rails (7.2.1)
       actioncable (= 7.2.1)
       actionmailbox (= 7.2.1)
@@ -904,7 +904,7 @@ DEPENDENCIES
   overcommit
   premailer-rails
   puma
-  rack (~> 2)
+  rack (~> 3)
   rack-cors
   rails
   rails-controller-testing